Dental impression tray

ABSTRACT

A pair of tray-forming members attached by a hinge along longitudinally adjacent edge portions and having inner adjacent edge portions which extend inwardly and upwardly so as to be mutually engaging when the tray-forming members are moved towards each other by action of the hinge. One of the tray-forming members has relatively perpendicular wall portions, one of which is positioned parallel to the other tray-forming member when attached by means of the hinge. A perforated plate is provided which is slidably removably disposed and retained by said other tray-forming member. A channel-shaped retainer is provided which is slidably removably engaged with the tray-forming members and which retains them in their U-shaped position while making an impression. When assembled, said impression tray has a generally U-shaped cross-section and said other tray forming member has a longitudinal radius of curvature which is generally the radius of curvature of adjacent series of teeth in a patient&#39;&#39;s mouth.

United States Patent [1 1 Neuwirth Oct. 16, 1973 DENTAL IMPRESSION TRAY Peyton Sidney Neuwirth, 1 14 Stratford Dr., Peoria, Ill.

May 1, 1972 [76] Inventor:

[22] Filed:

[21] Appl. No.: 249,269

Primary Examiner-Robert Peshock Attorney-John W. Malley et al.

[57] ABSTRACT A pair of tray-forming members attached by a hinge along longitudinally adjacent edge portions and having inner adjacent edge portions which extend inwardly and upwardly so as to be mutually engaging when the tray-forming members are moved towards each other by action of the hinge. One of the tray-forming members has relatively perpendicular wall portions, one of which is positioned parallel to the other tray-forming member when attached by means of the hinge. A perforated plate is provided which is slidably removably disposed and retained by said other tray-forming member. A channel-shaped retainer is provided which is slidably removably engaged with the tray-forming members and which retains them in their U-shaped position while making an impression. When assembled, said impression tray has a generally U-shaped cross-section and said other tray forming member has a longitudinal radius of curvature which is generally the radius of curvature of adjacent series of teeth in a patients mouth.

5 Claims, 4 Drawing Figures DENTAL IMPRESSION TRAY BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to dental instruments or accessories and pertains more particularly to a dental impression tray for use with the newer dental impression materials.

2. Prior Art With the increased use of certain types of compounds such as thiokols and silicones for the making of dental impressions, several means have been devised for maintaining the shape of the compound as well as retaining it in the impression tray. Where the compounds referred to have some fluidity, the devices used to hold the impression material have generally a cup shape and are made of perforated material so that the compound can flow through the holes and thus be maintained in the proper position in the tray.

When compounds are used which are not as free flowing, a tray without perforations is sometimes employed for making dental impressions, such as that disclosed in my previous Patent, No. 2,696,046, and over which the present invention represents an improvement. However, both types of devices, i.e., the perforated and unperforated impression trays, are very difficult to clean after the impression has been taken using these newer compounds, and because of this, many trays are discarded after minimal usage, which increases the expense of making dental impressions.

With these new materials available on the market today for use in dental impression trays, none of these devices proves to be satisfactory since the materials become so stiff, tough and adhesive that they can only be removed from the trays with greatdifflculty. In addition to this, the use of a perforated tray is necessary as a means for retaining the material within the impression tray. However, the perforated tray, because it allows the material to be extruded through the perforations as the impression is taken, does not provide the necessary support for these new materials, thus accuracy of the impression is sacrificed.

SUMMARY OF THE PRESENT INVENTION The present invention overcomes the above disadvantages by providing a removable perforated portion with a solid backup plate and thus provides the necessary support for the new materials, as well as a removable replaceable perforatedinsert for retaining the material, which does not have to be cleaned afterwards. The invention provides a pair of tray-forming members attached by a hinge along longitudinallyadjacent edge portions andhaving inner adjacent edge portions which extend inwardly and upwardly so as to be mutually engaging when the tray-forming, members are moved towards each other by action of the hinge. One of the tray-forming members has relatively perpendicular wall portions, one of which is positioned parallel to the other tray-forming member when attached by means of the hinge. A perforated plate is provided which is slidably removably disposed and retained by said other tray-forming member. A channel-shaped retainer is provided which is slidably removably engaged with the tray-forming members and which retains them in their U-shaped position while making an impression. When assembled, said impression tray has a generally U-shaped cross-section and said other tray forming member has a longitudinal radius of curvature which is generally the radius of curvature of adjacent series of teeth in a patient's mouth.

The dental impression tray of this invention is held in the patients mouth merely by the closure of the patients jaws against the tray, i.e., by biting down on the tray and thus obtaining an accurate impression of the teeth.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENT FIG. 1 is a perspective view of an illustrative embodiment of a dental impression tray of the present invention assembled for use.

FIG. 2 is a cross-sectional view of the tray taken on the line 2-2 of FIG. 1.

FIG. 3 is a cross-sectional view of the tray containing a dental impression compound and positioned in the patients mouth.

FIG. 4 is an exploded perspective view showing the channel-shaped retainer and the perforated plate relative to the tray-forming members.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the invention as assembled for use. The major parts of the impression tray assembly are a perforated plate 10, a channel-shaped tray 11 formed of relatively hinged members 12 and 14 and an impression tray retainer 16.

As shown in the cross-sectional view of the assembled impression tray of FIG. 2, the member 14 of the impression tray includes a web portion 18 and a perpendicular leg portion 20. The edge of. the web portion 18 is turned upwardly and inwardly to provide a flange 22. The member 12, which defines a second leg portion of the channel-shaped tray 11 has a lower edge portion which is turned inwardly and upwardly forming a flange 24 in such a way as to engage the flange 22 when the tray is assembled. Member 12 has its upper edge bent inwardly and downwardly forming a flange 26.

As best seen in FIGS. 1 and 4, the member 12 has a longitudinal radius of curvature which is designed to generally match the curvature of a patients jaw as the impression tray is positioned in his mouth. The perforated plate 10, also having a similar radius of curvature, is frictionally held in the member 12 of the impression tray by the flanges 24 and 26 so as to be slidably removable from the member 12. The perforated plate 10 may also have a transverse radius of curvature to allow the dental impression compound to flow behind the plate for better retention of the compound within the assembly.

Referring again to FIG. 2, a hinge 28, 28a is attached to the members 12 and 14 by solder or other suitable means. The impression tray retainer 16 is of a generally U-shaped cross-section having side portions 30 and 32 which are inclined slightly inwardly in a non-parallel condition when the retainer 16 is not in use. The portions 30-and 32 are resiliently forced outwardly when the retainer 16 is in its operative position, thus applying inward forces against the members 12 and 14 of the impression tray in order to keep the assembly tightly secured.

Referring now to FIG. 3 and the manner in which the invention is used, a suitable impression compound 34 is placed in the assembled dental impression tray. The

impression compound is forced into the perforations of plate and is retained thereby but is not able to freely flow through the perforations because of the support provided by the hinged member 12 of the impression tray assembly. The tray is then positioned in the patients mouth in such a manner that a tooth 36 of which the impression is to be taken is forced down into the compound as the patient closes his mouth and thereby making the desired impression.

After the impression is obtained, the impression tray is removed from the patients mouth, and the compound is allowed to set or harden. The retainer 16 is removed from the assembly and the member 12 may be rotated about the axis of the hinge 28, 28a, thus allowing the hardened compound to be removed by sliding the perforated plate 10 out of the hinged member 12. Any impression compound material remaining in the impression tray, for instance on the bottom wing portion 18 or the side wing portion 20, may be easily removed. A new perforated plate 10 may then be inserted in the member 12, and the impression tray can then be reassembled so as to be ready to be used for the taking of the next impression.

Although the foregoing description illustrates the preferred embodiment of the present invention, it will be apparent to those skilled in the art that variations are possible. All such variations as would be obvious to those skilled in the art are intended to be included within the scope of this invention.

What is claimed is:

1. An impression tray comprising a channel-shaped tray having a web member and two leg members, one of said leg members being hinged to said web member for swinging movement relative thereto, another of said leg members being fixed to said web member so as to allow said one leg member to be positioned on one side of a patients teeth and said other leg member to be positioned on an opposite side of said teeth; a perforated plate disposed along and generally coextensive with the inner surface of said one leg member; means for releasably retaining said perforated plate in engagement with said one leg member; and means for releasably retaining said impression tray in said channel shape.

2. An impression tray as defined in claim 1 wherein said one leg member is curved so as to generally conform to the radius of curvature defined by adjacent teeth in a patients mouth.

3. An impression tray as defined in claim 2 wherein said perforated plate generally conforms to the radius of curvature of said one leg member.

4. An impression tray as defined in claim 1 wherein said means for releasably retaining said impression tray in said channel shape is a slidably removable generally channel-shaped member having shaped flanges engaging said leg members when positioned to form said generally channel-shaped tray.

5. An impression tray comprising:

a pair of tray forming members attached by a hinge along longitudinally adjacent edge portions having inner adjacent edge portions extending inwardly and upwardly so as to be mutually engaging when said tray forming members are moved towards each other, one of said tray forming members having relatively perpendicular wall portions one of which is disposed generally parallel to the other tray forming member, said other tray forming member having an opposite edge portion extending inwardly and downwardly and parallel to said inner adjacent edge portions when said edge portions are engaged with one another;

a channel-shaped retainer slidably engaged with the tray-forming members and having spaced flanges engaging said other tray-forming member and the wall portion parallel thereto; perforated plate slidably removably disposed between said inner edge portion and said opposite edge portion of said other tray-forming member.

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1. An impression tray comprising a channel-shaped tray having a web member and two leg members, one of said leg members being hinged to said web member for swinging movement relative thereto, another of said leg members being fixed to said web member so as to allow said one leg member to be positioned on one side of a patient''s teeth and said other leg member to be positioned on an opposite side of said teeth; a perforated plate disposed along and generally coextensive with the inner surface of said one leg member; means for releasably retaining said perforated plate in engagement with said one leg member; and means for releasably retaining said impression tray in said channel shape.
 2. An impression tray as defined in claim 1 wherein said one leg member is curved so as to generally conform to the radius of curvature defined by adjacent teeth in a patient''s mouth.
 3. An impression tray as defined in claim 2 wherein said perforated plate generally conforms to the radius of curvature of said one leg member.
 4. An impression tray as defined in claim 1 wherein said means for releasably retaining said impression tray in said channel shape is a slidably removable generally channel-shaped member having shaped flanges engaging said leg members when positioned to form said generally channel-shaped tray.
 5. An impression tray comprising: a pair of tray forming members attached by a hinge along longitudinally adjacent edge portions having inner adjacent edge portions extending inwardly and upwardly so as to be mutually engaging when said tray forming members are moved towards each other, one of said tray forming members having relatively perpendicular wall portions one of which is disposed generally parallel to the other tray forming member, said other tray forming member having an opposite edge portion extending inwardly and downwardly and parallel to said inner adjacent edge portions when said edge portions are engaged with one another; a channel-shaped retainer slidably engaged with the tray-forming members and having spaced flanges engaging said other tray-forming member and the wall portion parallel thereto; a perforated plate slidably removably disposed between said inner edge portion and said opposite edge portion of said other tray-forming member. 